The present invention relates to an improved ankle brace. More particularly, it relates to an ankle brace including single direction stretch material along a rear portion to facilitate near-normal flexion and extension movements while limiting inversion, eversion and rotational movements.
The human ankle joint is a unique anatomical structure. The ankle includes seven bones, referred to as tarsal bones, one of which is a talus or ankle bone. The talus bone forms a lower half of an ankle joint. The upper half of the ankle joint is formed by tibia and fibula bones of the lower leg. The lower portion of the tibia forms a medial malleolus or inner portion of the ankle. The lower portion of the fibula forms a lateral malleolus or outer portion of the ankle. The fibula and tibia are held together by ligaments and form a mortice to receive the talus.
A relatively complex ligament system holds the ankle joint together. The ankle, or tibiofibular, joint includes three separate articulations; the inferior tibiofibular joint which is the articulation between the lateral malleolus and the tibia, the tibiofibular union which is the union of the shafts of the tibia and fibula by an interosseous membrane that consists of numerous short fibers which pass transversely from one articular surface to the other, and a superior tibiofibular articulation which is an articulation between the head of the fibula and a fibular facet of the tibia. During flexion in which the foot is pivoted toward the leg, the fibula tends to be displaced upward. Conversely, an extension movement, or pivoting of the foot away from the leg, the fibula tends to be displaced downward. These movements are normally resisted by the interosseous membrane. However, normal walking movements involve the simple flexion and extension of the foot relative to the leg.
While the human ankle is constructed to be highly durable, injuries can and do happen. Oftentimes during strenuous activities or sports participation, the foot is forced into an inversion or eversion position. Inversion is movement of the foot inward with respect to the leg. Conversely, eversion is a sideways, outward movement of the foot with respect to the leg. While the ankle joint structure does allow for minor natural inversion or eversion, overexertion in either of these directions results in stretching of the ankle joint, more commonly referred to as an "ankle sprain". For example, a common basketball or volleyball-related injury occurs when a participant lands on a side of the foot, causing the ankle to "roll" in an inverted or everted fashion. Alternatively and even more problematic is a bone fracture of one of the ankle bones. For example, a common skiing-related injury occurs when the foot is severely twisted with respect to the leg, fracturing the lateral or medial malleoli.
Immobilization of the ankle joint is commonly required to facilitate requisite healing following injury. Obviously, when a bone fracture has occurred, an immobilizing cast is required. However, for less severe injuries, the ankle need only be immobilized so as to restrict inversion, eversion and twisting movements. In other words, where the injury is such that the person may still engage in flexion and extension movements, such as normal walking or running, the ankle need only be partially immobilized. Normal flexion-extension of the foot will not magnify or otherwise aggravate the injury.
One common method for partially immobilizing an ankle is wrapping athletic tape around the person's foot, ankle and lower leg. To provide additional support, the user's ankle and lower leg is taped to the user's shoe. While the athletic taping approach is widely accepted, it does not provide support for an adequate period of time. Once applied, repeated movement of the foot causes the tape to loosen. Thus, after as little as 15 minutes of activity, the tape no longer provides the necessary inversion, eversion and twisting support required to prevent injury. Further, while a single roll of athletic tape is inexpensive, constantly retaping the injured area will, over time, require a relatively significant expenditure.
In view of the above-described problems associated with taping an injured ankle, various reusable ankle braces have been developed. Generally speaking, the standard ankle brace is designed to mimic the effects of the taping approach, but for a longer period of time and at a reduced cost. The standard ankle brace is basically a boot-shaped structure defined by a lateral member and a medial member. The lateral and medial members are configured to approximately match the contours of the lateral and medial members of the ankle, respectively. While flexible, the members are made from a non-stretch material. The members define an upper or calf opening for receiving and fitting about the user's calf and dorsal opening for receiving and fitting about the dorsal portion of the user's foot. Thus, the user's toes normally extend from the boot. With this configuration, the boot can accommodate a wide variety of different width feet. Further, the boot normally includes a slit or opening at the heel to facilitate positioning the foot/ankle brace into an athletic shoe. Finally, a front closure device, such as a shoelace, is used to tightly secure the ankle brace about the user's foot.
Unlike athletic tape, the above-described ankle brace does not normally lose its resiliency over time. Therefore, the ankle brace can provide the long-term support not otherwise found with athletic tape. Unfortunately, however, the standard ankle brace design has several drawbacks.
Unlike a permanent cast, the purpose of taping or use of an ankle brace is to partially immobilize the ankle joint. Once again, most ankle-related injuries, such as an ankle sprain, are not further traumatized by flexion and/or extension movements. The standard ankle brace design, however, does not allow for this type of movement. Instead, the standard ankle brace limits all movements. Thus, a person wearing a standard ankle brace is unduly restricted from performing normal range walking or running movements that require flexion and extension. Where the ankle brace is worn as a precautionary measure, the user's performance again will be unnecessarily hindered as he or she is prevented from making normal movements. Further, because the ankle brace is essentially clamped over the user's Achilles tendon, tendinitis may result.